This invention relates in general to the use of magnetic pulse forming techniques that can be used to deform a metallic workpiece to a desired shape. This invention also relates in general to the use of magnetic pulse welding techniques that can be used to permanently secure two metallic workpieces together. In particular, this invention relates to a method and apparatus for monitoring the performance of a magnetic pulse forming process or a magnetic pulse welding process over a period of time and for adjusting the parameters of such magnetic pulse forming or welding processes when necessary to maintain consistency in the operation thereof.
Magnetic pulse forming and magnetic pulse welding are well known processes that can be used in connection with workpieces that are formed from metallic materials. Magnetic pulse forming techniques are typically used to deform a metallic workpiece to a desired shape. Typically, a magnetic pulse forming process is performed by initially disposing a portion of a metallic workpiece either about or within an electromagnetic inductor coil. The inductor coil is then energized by a passing a high-energy pulse of electrical current therethrough so as to generate an intense electromagnetic field either about or within the portion of the workpiece. When this occurs, a large pressure is exerted on the exterior or interior of the workpiece, causing it to deform either inwardly away from the inductor coil (when the inductor coil is disposed about the exterior of the workpiece) or outwardly away from the inductor coil (when the inductor coil is disposed within the interior of the workpiece). If desired, the workpiece may be deformed inwardly into engagement with an inner mandrel or outwardly into engagement with an outer die so that the workpiece is deformed to have a precise desired shape.
Magnetic pulse welding techniques are typically used to permanently secure two metallic workpieces together. Typically, a magnetic pulse welding process is performed by initially disposing two portions of first and second metallic workpieces in a concentric, axially overlapping relationship. Next, the overlapping portions of the first and second metallic workpieces are disposed either about or within an electromagnetic inductor coil. The inductor coil is then energized by a passing a high-energy pulse of electrical current therethrough so as to generate an intense electromagnetic field either about or within the overlapping portions of the first and second workpieces. When this occurs, a large pressure is exerted on one of the first and second workpieces, causing it to move toward the other of the first and second workpieces at a high velocity. If the inductor coil is disposed about the exterior of the two workpieces, then the outer workpiece is deformed inwardly into engagement with the inner workpiece. If, on the other hand, the inductor coil is disposed within the interior of the two workpieces, then the inner workpiece is deformed outwardly into engagement with the outer workpieces. In either event, the high velocity impact of the first and second workpieces cause the two workpieces to become permanently secured together.
As is apparent from the above descriptions, magnetic pulse forming techniques and magnetic pulse welding techniques result in the generation of high energy electromagnetic fields either about or within the workpiece or workpieces. To accommodate the reactance forces that are generated by these high energy electromagnetic fields, it is usually necessary that the inductor coil be manufactured in such a manner as to be very strong from a mechanically standpoint. However, over a period of time, the repeated generation of such reactance forces can cause physical changes to occur in the magnetic pulse forming or welding apparatus. For example, the shape or spatial orientation of the inductor coil can change slightly as a result of the repeated generation of these reactance forces. These physical changes in the magnetic pulse forming or welding apparatus can result in localized changes in the intensity of the electromagnetic field over a period of usage, thus resulting in undesirable variances the stability of the magnetic pulse forming or welding process. Thus, it would be desirable to provide a method and apparatus for monitoring the performance of a magnetic pulse forming process or a magnetic pulse welding process over a period of time and for adjusting the parameters of such magnetic pulse forming or welding processes when necessary to maintain consistency in the operation thereof.